The Best Way to Compress and Obfuscate Javascript Code Online Completely Free.

Ajax-based Rich Internet Applications make heavy use of JavaScript. As rich web applications are being built with larger JavaScript, the need for JavaScript compression to keep bandwidth and page load times as small as possible by decreasing the size of the files served is becoming more important for more enjoyable user experiences.

CompressJavaScript.com works like a compressor by taking your JavaScript source code and compressing it by removing comments, whitespace, line feeds, and optionally by shortening function parameters and variable names. Compressing JavaScript will reduce the script size, and may help your pages load faster and reduce bandwidth consumption. Moreover, with line feed removal and variable name compression, it provides obfuscation of the code, making it harder for the user to read the code. However, it won't stop a determined user from reformatting and reverse engineering the code.

Select Compression Method

Low Compression

Removes white space, comments and line feeds.

Medium Compression

Removes white space, comments and line feeds.
Encodes words to an alphanumeric value.

High Compression

Removes white space, comments and line feeds.
Encodes words to an alphanumeric value.
Shortens variable names.

Caution: All statements, including function declarations, must be terminated with semi-colons.

Optimizing Javascript for Better Web Performance/Experience

JavaScript files are highly compressible, in some cases by as much as 60 to 80 percent. Moreover, by grouping external JavaScripts and using compression, you can dramatically reduce their impact on page display speed and bandwidth usage.

You may find detailed information at: 7 Easy-to-Apply Tips to Improve Your Web Site Performance